Since ultraviolet light has sterilization capability, various devices for successively sterilizing a fluid such as water, by irradiation of the ultraviolet light, have been proposed.
In existing sterilization devices, a bulb such as a mercury lamp or a xenon lamp is employed as the ultraviolet light source. In addition, a fluid sterilization device has also been proposed that employs a light emitting diode (LED) that emits a light of a wavelength capable of sterilizing, as the ultraviolet light source.
The fluid sterilization devices thus far proposed include, for example, a sterilization device configured to pass an object to be sterilized through a hollow portion of an integrating sphere, and emit the ultraviolet light in the hollow portion thus to sterilize the object (see, for example, Japanese Patent No. 5432286), and a sterilization device including a straight tube constituting a flow path extending in a longitudinal direction, and configured to emit the ultraviolet light in the longitudinal direction to the fluid flowing in the straight tube (see, for example, Japanese Patent No. 6080937).